Element and PAH constituents in the residues and liquid oil from biosludge pyrolysis in an electrical thermal furnace.

Biosludge can be pyrolyzed to produce liquid oil as an alternative fuel. The content of five major elements, 22 trace elements and 16 PAHs was investigated in oven-dried raw material, pyrolysis residues and pyrolysis liquid products. Results indicated 39% carbon, 4.5% hydrogen, 4.2% nitrogen and 1.8% sulfur were in oven dried biosludge. Biosludge pyrolysis, carried out at temperatures from 400 to 800°C, corresponded to 34-14% weight in pyrolytic residues, 32-50% weight in liquid products and 31-40% weight in the gas phase. The carbon, hydrogen and nitrogen decreased and the sulfur content increased with an increase in the pyrolysis temperature at 400-800°C. NaP (2 rings) and AcPy (3 rings) were the major PAHs, contributing 86% of PAHs in oven-dried biosludge. After pyrolysis, the PAH content increased with the increase of pyrolysis temperature, which also results in a change in the PAH species profile. In pyrolysis liquid oil, NaP, AcPy, Flu and PA were the major species, and the content of the 16 PAHs ranged from 1.6 to 19 µg/ml at pyrolysis temperatures ranging from 400 to 800°C. Ca, Mg, Al, Fe and Zn were the dominant trace elements in the raw material and the pyrolysis residues. In addition, low toxic metal (Cd, V, Co, and Pb) content was found in the liquid oil, and its heat value was 7,800-9,500 kcal/kg, which means it can be considered as an alternative fuel.

Pyrolytic product characteristics of biosludge from the wastewater treatment plant of a petrochemical industry.

Biosludge was produced from the wastewater treatment plant of a petrochemical industry. The element compositions of pyrolytic residues, CO, CO(2), NOx, SOx, total hydrocarbons and detailed volatile organic compounds of pyrolytic gas, and C, H, N, S content and compositions in biofuel were determined in this study. Generally, 75-80% water content in sludge cakes and about 65-70% weight of water vapor and volatile compounds were volatilized during the drying process. Propene, propane, 1-butene, n-butane, isobutene, toluene and benzene were the major volatile organic compounds (VOCs) of the pyrolytic gas, and the concentrations for most of the top 20 VOC species were greater than 5 ppm. C(5)-C(9) compounds contributed 60% by weight of biofuel; 4-hydroxy-4-methyl-2-pentanone was the highest species, accounting for 28-53% of biofuel at various pyrolytic temperatures. Based on the dried residues, there was 8.5-13% weight in pyrolytic residues, 62-82% weight in liquid products (water and crude oil) and 5.8-30% weight in the gas phase after pyrolytic processing at 500-800 degrees C. Finally, 1.5-2.5 wt% liquid fuel was produced after the distillation process. The pyrolytic residues could be reused, the pyrolytic liquid product could be used as a fuel after distillation, and the pyrolytic gas could be recycled in the pyrolytic process to achieve non-toxic discharge and reduce the cost of sludge disposal.

Characteristics of water-soluble ionic species in fine (PM2.5) and coarse particulate matter (PM10-2.5) in Kaohsiung, southern Taiwan.

Eleven ionic species and fine and coarse particle mass concentrations of fine (PM2.5) and coarse (PM10-2.5) particulate matter were investigated in Kaohsiung, southern Taiwan. The PM2.5 and PM10-2.5 particulate concentrations were 49-64 and 34-37 microg x m(-3), respectively. Fifty-five to 64% of the particulate matter less than 10 microm in aerodynamic diameter (PM10) mass was attributed to the PM2.5. PM2.5 concentrations at Daliao (a rural and industrial complex area) were higher than at Tzuoying (an urban and industrial complex area). Ionic species contributed 45-53% and 42-45% of PM2.5 and PM10, respectively. Potassium ions (K+), sulfate (SO4(2-)), and ammonium (NH4+) were predominant in PM2.5, whereas sodium, calcium, and magnesium ions were foremost in PM10-2.5. Nitrate (NO3-) existed in both the PM2.5 and PM10-2.5. Chloride (Cl-), NO3-, and NH4+ concentrations were higher at night than during the day, and they were easily transferred into the gas phase by photochemical reactions and temperature-induced volatilization. The NH4+/SO4(2-) ratios were 2.6 and 2.5 at Daliao and Tzuoying, respectively, which indicated that both sampling sites were rich in NH4+. Therefore, ammonium nitrate would be present in the area.